Centrifugal device for treating gases or vapors with liquids

ABSTRACT

A centrifugating device for reacting gases or vapors with liquids or with liquid or solid substances finely distributed in liquids, comprises a centrically arranged rotor shaft to which rotor wheels are attached which carry centrifugating or fling members with reaction stages being formed by fixed partitions between the rotor wheels. The centrifugating members at least, in part, are made in the form of bristles, and baffles are located on the rotor wheels. The fling and baffle members serve to destroy and re-form the liquid surface.

ilnited States Patent 1 Mentschell CENTRIFUGAL DEVKCE FOR TREATING GASESOR VAPORS WITH LHQUllDS [75] Inventor: Hellmuth MentscheLErlangen,

Germany [73] Assignee: Siemens Aktiengeseiischait, Berlin and Munich,Germany [22] Filed: June 15, 1971 [21] Appl. No.: 153,208

[30] Foreign Application Priority Data June 18, 1970 Germany P 20 29994.9

52 us. c|....; 2 61/89, 55/230, 55/238, 55/403 [51] ,Int. Cl. B0ld 47/16[58] Field of Search 261/84, 8890; 55/230-231, 235, 237, 238, 400-409[56] References Cited UNITED STATES PATENTS 7/1936 Delamere 261/89 1Sept. 11, 1973 2,593,763 4/1952 Kapitza 261/89 2,601,519 6/1952 Hardy etal. 261/90 X 2,941,872 6/1960 Pilo et al 261/84 X 3,406,498 10/1968Wisting 261/89 X 3,474,597 10/1969 Eckert 261/84 X 3,538,657 11/1970Macrow.... 261/89 X 3,544,084 12/1970 Macrow 261/90 X PrimaryExaminerFrank W. Lutter Assistant Examiner-Vincent Gifford Attorney CurtM. Avery, Herbert L. Lerner et a1.

[ v ABSTRACT A centrifugating device for reacting gases or vapors withliquids or with liquid or solid substances finely distributed inliquids, comprises a vcentrically arranged rotor shaft to which rotorwheels are attached which carry centrifugating or fling members withreaction stages being formed by fixed partitions between the rotorwheels. The centrifugating members at least, in

part, are made in the form of bristles, and baffles are located on therotor wheels. The fling and baffle members serve to destroy and re-formtheliquid surface 11 Claims, 5 Drawing Figures CENTRIFUGAL DEVICE FOII'TREATING GASES ratus is used which'has a rotor, in which the gas isbrought into intimate contact with the liquid. These devices aredesigned so that large contact surfaces are provided and contact betweenthe gas and the liquid is possible over an extended period of time. Inthe British Pat. No. 1,026,291, for example, the liquid is atomized andsubjected, together with the gas, to circulation perpendicular to thedirection of rotation of the rotor.

If a gas is brought into contact with a liquid, absorption or a chemicalreaction takes place as a boundarysurface reaction. In most cases, thistakes place relatively rapidly, but onlyin a thin outer layer of thesurface of the liquid. The diffusion processes thereafter,

however,- whichtransport the absorbed gas or the reacor reactionproducts in the boundary layer between the liquid and the gas thereforeleads rapidly to a saturation of this contact surface and therefore to akind of barrier layer. The large absorption rate at the beginning of thereaction is therefore reduced rapidly. In the known device, therelativelyslow diffusion processes within the liquid determinelargelytherate at which the gas is absorbed and/or reacted.

It is an object of my invention to carry out the reaction of gases orvapors with liquids, solutions, suspensions or the like in such a mannerthat the diffusion rate has no appreciable influence on the absorptionprocess.

Another object of my invention is to provide apparatus in which thepurification of the gas with liquids is improved as compared with priorart apparatus.

Still another object of my invention is to provide such apparatus inwhich the power required to operate the apparatus is kept to a minimum.

Another object of my invention is to utilize thegas being purified indriving the centrifugal device.

Other objects, advantages and features of the present invention willbecome more apparent from the follow-- ing description.

To this end, and according to may invention, 1 pro-' vide a device forreacting gases or vapors with liquids or with liquid or solid substancesfinely distributed in liquids, com prising a centrically arranged rotorshaft to which rotor wheels are attached which carry centrifugatingmembers, reaction stages being formed by fixed partitions between therotor wheels. The centrifugating -members (hereafter also calledflingmembers") are at least, in part, made in theform of bristles, andbaffles are furthermore located on the rotor wheels. The fling.

by the separation fromthe fling member is continuously destroyed and anew surface generated. on the way from the fling to the baffle :memberthe liquid droplets come in contact with the gas, the reaction, forinstance, absorption or a chemical reaction, taking place at theboundary surface between the liquid and the gas. Immediately thereafter,upon impact with the baffle, the surface of the liquid droplet whichwould act as a barrier layer due to the charge with gas or reactionproduces, is destroyed and a renewed reaction of the gas with the liquidis made possible through the regeneration of the liquid surface. Therebythe reaction between the' gas and the liquid is not influenced bydiffusion processes.

The invention will be further described with reference to theembodiments thereof, illustrated by way of example on the accompanyingdrawings in which:

FIG. 1 is a cross-sectional view of an embodiment of the centrifugaldevice for treating gases with liquids according to the invention; FIGS.2 through 4 are cross-sectional views of additional embodiments ofreaction stages used in the cen trifugal device; and

FIG. 5 is an enlarged sectional view .of a rotorwheel used in thecentrifugal device of my invention.

Referring to the drawings, and in particular to FIG. 1, the coaxialreaction centrifuge is shown with a hous ing 1 and a rotor shaft 2. Therotor can be driven by a motor (not shown). However, the gas itselfwhich is re. acting with the liquid can also be advantageously used todrive the rotor. For that purpose, a turbo drive is provided adjacent toan inlet opening 3, through which the compressed gas is fed to thereaction centrifuge. The turbo'drive includes at least one nozzle 4located at the opening 3 which directs the gas jet against guide vanes 5which are mounted on a flange 6 attached to the rotor shaft 2. If a gasmixture reacts with a liquid in such a manner that not all componentsare absorbed by the liquid, it is advisable to react the compressed gasmixture with the liquid first in order to carry out this process at thehighest possible pressure. Only the residual gas, which is under lesspressure due to friction losses, is then used to drive the reactioncentrifuge.

The path of the gas in the reaction centrifuge is indicated by solidlines. After leaving the drive arrangement, it enters the first of thereaction stages 7 at the rotor shaft. The path to the wall of thehousing'is blocked to the gas by a cylindrical partition 8, which isattached at a bottom surface 9 of a rotor wheel 16 of the lowestreaction stage 7 and is immersed in the liquid which is situated in thelower part of the reaction centrifuge, which is designed as a liquidreservoir It In the individual reaction stages 7, the gas passes byfling members 11 and baffle members 12 inthesarne direction as theliquid. However, from one reaction stage to another, the gas isconducted against the flow of the liquid. After leaving the lastreaction stage the gas exits by an outlet opening 13. The liquid is fedinto the reaction centrifuge through an inlet opening 14, moves throughthe individual reaction stages in the manner indicated by the dashedlines and is collected in the liquid reservoir 10 and leaves thereaction centrifuge by an outlet opening 15.

l The rotor wheels 7 of the device according to FIG. I areadvantageously provided with smooth top 9a and bottom 9 surfaces eachwhere facing the wall of the housing 1,-the partitions and the rotorshaft 2, and are only provided with the discharge and entrance openings,arranged parallel to the rotor shaft, for the liquid and the gas. Inthis case, the fling and baffle members arranged between the top andbottom surfaces of the rotor wheels form self-contained units, whereindue to the smooth design of the boundary surfaces, the pressure lossescaused by friction with the gas are kept to a minimum. Due to thearrangement of the fling and baffle members in the rotor wheels designedin this manner, the friction losses between the gas, the liquid .and theparts of the rotor wheels also can be kept to a minimum, as thedestruction and regeneration of the liquid surfaces takes place insidethe rotor wheelsat approximately equal velocity of the rotating rotorwheel, the liquid and the gas. The reaction of the gas with the liquid,for instance, the absorption of carbon dioxide by aqueous solution ofalkali compounds with basic reaction, can therefore be carried out inthis manner be cause the charging speed of the liquid with the gas doesnot depend on the differential speed between the liquid and the gas, buton the frequency with which the contact surface is destroyed andregenerated.

As described above, the fling members of the device, according to theinvention, are at least in part made in the form of bristles, whichcauses the separated liquid to be exclusively in the form of smalldroplets being carried from the fling members and in this manner, alarge contact surface is provided. Stainless steel or plastics, such aspolytetrafluorethylene, polyvinylchloride,

etc., can be used for the fling members.

FIG. 2 shows. two reaction stages 21 and two rotor wheels 22,respectively, of another embodiment of my invention including a wall 23of the housing and a rotor shaft 24. Through openings 25 of a fixedpartition 26, the gasenters a space 27 of the lower reaction stage whichis situated below the rotor wheel. The gas passes through holes 28 ofthe rotor wheel into a space 29 in which it comes in contact with theliquid. Through openings 30 in a wall 31, which delineates this spaceand which can be designed as a baffle, the gas leaves the space 29,passes a fling member 32 and enters a space 33,-in which it is broughtinto intimate contact rotor wheel. The path back into the space 27underneath the bottom surface 35 is blocked by the liquid above thepartition 26 and the cylindrical rib 36 of the rotor wheel, which isimmersed in the liquid. The gas, therefore, takes the path via the topsurface 37 of the rotor wheel and enters the next reaction stage throughopenings 38 in partition39. The path back into the space 29 is blockedby the liquid, which is in a pan 40 and a wall 4] which extends into theliquid. In this reaction stage, and possibly in other reaction stages,this process is repeated until the gas finally leaves the reactioncentrifuge after passing through the last reaction stage.

The liquid which is fed to the gas counterstream-wise This partition,which is part of the top surface of the rotor wheel, is provided with anembossed mosaic pattern, at least partially on the inside and istherefore designed as a baffle member. In this manner, destruction andregeneration of the liquid surface takes place in space 52, as well asthe intensive reaction of the gas with the liquid. The liquid leaves thespace 52 thorugh passage openings 53 of the bottom surface 54 of therotor wheel and drips on the partition 39. Due to the inclination ofthis fixed partition, the liquid runs off in the direction toward therotor shaft and is collected in a space 55. If the latter issufficiently full, the liquid leaves this space via overflow slots 56and leaves the reaction stage through holes 57 of the partition 39. Itsubsequently drips to the pan 40 of the lower reaction stage. Afterpassing through all the reaction stages, the liquid is discharged fromthe reaction centrifuge.

FIG. 3 shows two reaction stages of another embodiment of the deviceaccording to my invention, in which several groups are arranged in eachreaction stage,

each consisting of a fling member and a baffle member. The number of thegroups of fling and baffle members can be chosen in accordance with theoperating conditions. The gas and the liquids are fed in in this design,in theindividual reaction stages, over an extended path in the samedirection, and counterstream-wise only between the individual reactionstages. More particularly, the wall of the housing is designated 61 andthe rotor shaft 62. The fixed partitions 63, which again are inclined,are also crimped at 64, which is deep enough that the ribs 65 in thebottom surfaces 66 of the rotor wheels dip into the liquid that collectson the partitions. The bafi'les are designated 67 and the fling members68. In one fling member 68a, a bristle-like structure is indicated, thisstructure being utilizable in all the embodiments of my invention.

The gas and the liquid take the same path within the reaction stage inthis embodiment as was explained in connection with the embodiment ofFIG. 2. The passage of the gas and the liquid from one reaction stage toanother, however, takes place in the embodiment described here throughthesame respective holes 69 in the partitions 63. The cross-section ofthe holes 69 is here selected so that the rising gas does not preventthe liquid from running off. i In FIG. 4, a reaction stage of a furtherembodiment of a reaction centrifuge is shown. In this embodiment,several groups consisting of one fling and baffle member each arearranged in each reaction stage in series and on top of each other. Thebaffle members are designated 71 and the fling members 72. Thisarrangement is advantageously chosen if operation with larger throughoutrates of gas and liquid is involved, because due to the presence of many.fling and baffle members in one reaction stage, the pressure losseswhich occur in the passing of the media is kept low.

FIG. 5 shows an enlarged sectional view of a rotor wheel. In thisembodiment, the fling members 81 consist of fine-mesh screens, the endsof which are slit open. The baffle members 82 in the interior of therotor wheel are provided at their lower region with passage openings 83.The baffle members have an embossed mosaic pattern in their upperregion, indicated by 84 in the Figure.

The baffles arranged inside the rotor wheels as shown in FIGS. 2 through5 have passage openings for the gas and the liquid in their lowerregions, which are connected with the bottom surface of the rotor wheel.While-the gas passes through these openings unimpeded, the liquid comesin contact with the fling members attached at these points to the rotorwheel, climbs up on the former and is thrown off by the centrifugalforce. As the baffle farthest from the rotor axis can preferably be usedthe outer end wall of the rotor wheel, which is part of the top surface,and this end wall is provided with an embossed mosaic pattern on theinside, at least partially, but has no passage opening for the gas andthe liquid at its lower region.

The fling and baffle members arranged on the rotor ,wheels of thereaction centrifuge can advantageously be made of annular shape, and theentire available therefore, they are attached on the rotor wheels insuch a manner that the part made of bristles points toward the adjacentbaffle member of the same rotor wheel which is at a greater distancefrom the rotor axis. In this manner, the separating liquid is throwncompletely onto the upper area of the baffles, which are not providedwith openings.

The advantage obtained over prior art fling members which are parallelto the rotor axis is that no noticeable gas pressure loss occurs. Thefine-mesh fabric of the fling members is coated during the operationwith a film of liquid. If fling members are arranged vertically asboundary surfaces, a considerable pressure must be exerted to push thegas through them, while in the oblique arrangement of the fling membersaccording to the invention, the gas passes unimpeded and no pressureloss occurs. This is of particular importance if the device serves topurify gases which are used for the operation of fuel cells. As theenergy required for the operation of auxiliary power generators is tobesupplied by the fuel cell itself, the efficiency of the latter decreaseswith every energy-consuming process. This is also the case if largepressure losses must be made up in the purification of the gases used.

The baffles of the reaction centrifuges illustrated above consist ofwalls which are advantageously arranged on the rotor wheels parallel tothe rotor axis. It is advantageous that they furthermore include, atleast partially, an embossed mosaic pattern. The impinging liquiddroplets are thereby completely destroyed and through the regenerationof the surface of the liquid, a completely new contact surface isavailable for further reaction between the gas and the liquid.

If in such fuel cells, hydrogen is used as the fuel gas, the hydrogenrequired for this purpose is frequently made in a generator by reactingmethanol and water vapor with oxygen. Here, however, a mixture isgenerated which contains approximately 75% by volume of hydrogen and 25%by volume of carbon dioxide. The carbon dioxide contained in the gasmixture must be removed if an alkaline electrolyte is used in the fuelcell. This is effectively done by removing the carbon dioxide by analkazide solution, for instance, an aqueous solution of potassiumalaninate; here the carbon dioxide is absorbed in the form of hydrogencarbonate. The absorption capacityof the alkazide solution for thecarbon dioxide is strongly influenced by the described rapid formationof a barrier layer. The device according to the invention counteractsthis process through the continuous destruction and regeneration of theliquid surface, and in this manner makes possible a fast reaction of thecarbon dioxide with the alkazidesolution. The device is alsoparticularly well suited for this application because the gas mixturewhich is supplied by the generator under a certain pressure can be usedin a gas turbine for driving the reaction centrifuge. Due to the designof the device, especially of the fling members, the baffles and therotor wheels, the pressure loss within the reaction centrifuge is verysmall. Only the required acceleration of the liquid, i.e., the alkalinesolution, from the condition at rest to a final velocity is the mainenergy-consuming process.

As described in FIG. 1, advantageously, the gas reacting with the.liquid can be used, before or after the reaction, to drive the coaxialreaction centrifuge. This is achieved by making the pressurized gasserve as the drive medium for a turbo drive. The turbo drive and therotor are advantageously mounted here on a common shaft in the samehousing.

In addition to these preferred application possiblities the deviceaccording to the invention can find application for any other reactionsof gases or vapors with liquids in which diffusion processes impedeabsorption or a chemical reaction. In this context, also solutions,suspensions or emulsions can be reacted with gases or vapors, i.e.,solid or liquid substances dissolved or finely distributed in liquids.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in the above apparatus withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description and shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

I claim:

1. Centrifuge device for treating gases or vapors with liquids or withliquid or solid substances finely distributed in liquids, comprising agas inlet and outlet, a liquid inlet and outlet, a centrically arrangedrotor shaft, rotor wheels attached'to said rotor shaft, said rotorwheels carrying centrifugating members disposed at an acute angle withrespect to said rotor shaft, fixed partitions being disposed betweensaid rotor wheels and forming reaction stages, said centrifugatingmembers including bristles, and baffle members located on the rotorwheels spaced apart from said centrifugating members.

2. Centrifuge device according to claim I, wherein each of said rotorwheels comprise one top surface and wards a respective baffle memberdisposed adjacently on the same rotor wheel at a larger distance fromthe rotor shaft than said centrifugating member.

5. Centrifuge device according to claim 1, wherein said baffle memberslocated inside said rotor wheels comprise walls arranged parallel to theaxis of the rotor, said walls being formed of an embossed mosaicpattern, and an opening in the lower region of said walls for passage ofthe gases and the liquid.

6. Centrifuge device according to claim 1, wherein said centrifugatingmembers and said baffle members are of annular shape.

7. Centrifuge device according to claim 1, wherein at least onecentrifugating member and one baffle member are located on each rotorwheel.

8. Centrifuge device according to claim 1, wherein groups comprising onecentrifugating member and one baffle member each are arranged on therotor wheel in each reaction stage in series.

9. Centrifuge device according to claim 1, wherein groups comprising onecentrifugating member and one baffle member each are arranged on therotor wheel in each reaction stage on top of each other.

10. Centrifuge device according to claim 1, wherein said gases are underpressure and drive the centrifugating device before or after reactionwith said liquid.

11. Centrifuge device according to claim 1, wherein each of said rotorwheels comprise one top surface and one bottom surface, said top andbottom surfaces being smooth in areas facing the exterior of the rotorwheel, and discharge and entrance openings for said liquid beingparallel to said rotor shaft, said centrifugating and baffle membersbeing arranged between said top and bottom surfaces.

I t IF

1. Centrifuge device for treating gases or vapors with liquids or withliquid or solid substances finely distributed in liquids, comprising agas inlet and outlet, a liquid inlet and outlet, a centrically arrangedrotor shaft, rotor wheels attached to said rotor shaft, said rotorwheels carrying centrifugating members disposed at an acute angle withrespect to said rotor shaft, fixed partitions being disposed betweensaid rotor wheels and forming reaction stages, said centrifugatingmembers including bristles, and baffle members located on the rotorwheels spaced apart from said centrifugating members.
 2. Centrifugedevice according to claim 1, wherein each of said rotor wheels compriseone top surface and one bottom surface, said top and bottom surfacesbeing smooth in areas facing the exterior of the rotor wheel, anddischarge and entrance openings for said liquid and gases being parallelto said rotor shaft, said centrifugating and baffle members beingarranged between said top and bottom surfaces.
 3. Centrifuge deviceaccording to claim 1, wherein said centrifugating members comprisefine-mesh screens, the ends of which are slit open.
 4. Centrifuge deviceaccording to claim 1, wherein each of said centrifugating members isdirected towards a respective baffle member disposed adjacently on thesame rotor wheel at a larger distance from the rotor shaft than saidcentrifugating member.
 5. Centrifuge device according to claim 1,wherein said baffle members located inside said rotor wheels comprisewalls arranged parallel to the axis of the rotor, said walls beingformed of an embossed mosaic pattern, and an opening in the lower regionof said walls for passage of the gases and the liquid.
 6. Centrifugedevice according to claim 1, wherein said centrifugating members andsaid baffle members are of annular shape.
 7. Centrifuge device accordingto claim 1, wherein at least one centrifugating member and one bafflemember are located on each rotor wheel.
 8. Centrifuge device accordingto claim 1, wherein groups comprising one centrifugating member and onebaffle member each are arranged on the rotor wheel in each reactionstage in series.
 9. Centrifuge device according to claim 1, whereingroups comprising one centrifugating member and one baffle member eachare arranged on the rotor wheel in each reaction stage on top of eachother.
 10. Centrifuge device according to claim 1, wherein said gasesare under pressure and drive the centrifugating device before or afterreaction with said liquid.
 11. Centrifuge device according to claim 1,wherein each of said rotor wheels comprise one top surface and onebottom surface, said top and bottom surfaces being smooth in areasfacing the exterior of the rotor wheel, and discharge and entranceopenings For said liquid being parallel to said rotor shaft, saidcentrifugating and baffle members being arranged between said top andbottom surfaces.